"Usage" documentation a little unclear

[Scott Edwards]

In the "Usage" document on grep at 

http://www.gnu.org/software/grep/doc/grep_13.html#SEC13

I'm not sure about this section:

> 13. Why are my expressions whith the vertical bar fail? 
>
>
> 
/bin/echo "ba" | egrep '(a)\1|(b)\1'
>
> The first alternate branch fails then the first group was not in the
> match this will make the second alternate branch fails. For example,
> "aaba" will match, the first group participate in the match and can be
> reuse in the second branch.

I am assuming the headline was supposed to be: "Why are my expressions
WITH the vertical bar FAILING?"

I am not clear at all what the explanation is trying to say.  Maybe I
just need to brush up on my regular expressions.  I do suspect that
"fails" should be "fail" and "reuse" should be "reused".

Thanks
  -Scott